JEAN LAFITTE -- From a Cessna flying 4,000 feet above Louisiana's coast, what strikes you first is how much is already lost. Northward from the Gulf, slivers of barrier island give way to the open water of Barataria Bay as it billows toward an inevitable merger with Little Lake, its name now a lie. Ever-widening bayous course through what were once dense wetlands, and a cross-stitch of oil field canals stamp the marsh like Chinese characters.

Saltwater intrusion, the result of subsidence, sea-level rise and erosion, has killed off the live oaks and bald cypress. Stands of roseau cane and native grasses have been reduced to brown pulp by feral hogs, orange-fanged nutria and a voracious aphid-like invader from Asia. A relentless succession of hurricanes and tropical storms -- three last season alone -- has accelerated the decay. In all, more than 2,000 square miles, an expanse larger than the state of Delaware, have disappeared since 1932.

Out toward the horizon, a fishing village appears on a fingerling of land, tenuously gripping the banks of a bending bayou. It sits defenseless, all but surrounded by encroaching basins of water. Just two miles north is the jagged tip of a fortresslike levee, a primary line of defense for New Orleans, whose skyline looms in the distance. Everything south of that 14-foot wall of demarcation, including the gritty little town of Jean Lafitte, has effectively been left to the tides.

Jean Lafitte may be just a pinprick on the map, but it is also a harbinger of an uncertain future. As climate change contributes to rising sea levels, threatening to submerge land from Miami to Bangladesh, the question for Lafitte, as for many coastal areas across the globe, is less whether it will succumb than when -- and to what degree scarce public resources should be invested in artificially extending its life.

Grant Gold and Tim Wallace, The New York Times

One sweltering evening in July last year, almost everyone from around Lafitte gathered near dusk at the bayou's edge to celebrate the expenditure of nearly $4 million of those scarce public resources. There were shrimpers and crabbers, tug captains and roughnecks, teachers and cops. All had come for the ribbon-cutting for a grand new seafood pavilion, the latest gambit by the longtime mayor, Timothy Kerner, to save the town from drowning.

Free beer sloshed in plastic cups as folks ambled about the cavernous, open-sided shed, sampling shrimp remoulade and alligator-stuffed mushrooms. Once the politicians had finished flattering one another from the podium, a band, fronted by Cajun fiddler Amanda Shaw, cranked up a rollicking fais do-do.

Amid the celebration, a fireplug of a man in crisp jeans and a starched white shirt cheek-kissed and bro-hugged his way through the crowd. This was Timmy Kerner's party. In his third decade as mayor, Kerner had managed to persuade the parish, state and federal governments to pay for his signature showcase at the entry to town.

It may seem counterintuitive to keep building on land that is submerging. But Kerner did not see it as his job to take a 10,000-foot view. In the years since Hurricane Katrina, he had grown weary of being rebuffed in his quixotic campaign to encircle Lafitte with a tall and impregnable levee. He could rhapsodize all he wanted about preserving his community's authentic way of life. The cost-benefit calculus -- more than $1 billion to protect fewer than 7,000 people -- always weighed against him.

Jean Lafitte Mayor Tim Kerner greets residents at the ribbon-cutting ceremony for the $3 million Jules Nunez Seafood Pavilion and AJ & Sheron Fabre Market on July 15, 2017. The market is part of an effort to boost the tourism economy and to provide lawmakers with an incentive to protect the oft-flooded town with a new levee. (Chris Carmichael, The New York Times)

So he had set out to change it. His strategy was to secure so much public investment for Jean Lafitte that it would eventually become too valuable to abandon. In a decade, he had built a 1,300-seat auditorium, a library, a wetlands museum, a civic center and a baseball park. Jean Lafitte did not have a stoplight, but it had a senior center, a medical clinic, an art gallery, a boxing club, a nature trail and a visitor center where animatronic puppets acted out the story of its privateer namesake.

Some of the facilities had been used sparingly, and many at the grand opening questioned whether the seafood pavilion would be much different. To the mayor that was largely beside the point. What mattered was that the structure existed, that its poured concrete and steel beams made Lafitte that much more permanent.

"Do we lose that investment, or do we protect it?" Kerner asked, barely audible above the din. "I hope people will see that, hey, not only are we fighting hard to exist, but, you know, maybe this place is worth saving."

The sky began to dim over the bayou. "It's such a beautiful place, and it's getting prettier by the day," he said, ticking off his improvement projects. "This is just another step at building the community. It sends a message that we're not going anywhere.

"No matter what, we're not leaving."

'We are literally in a race against time'

This map shows Louisiana's projections of land that will be lost over 50 years if no action is taken to restore wetlands and barrier islands. (The New York Times)

'We are literally in a race against time'

Louisiana's "working coast" is dotted with communities that, like Lafitte, may not outlast the people who currently live there: Cocodrie, Delacroix, Dulac, Grand Isle, Isle de Jean Charles, Kraemer, Leeville, Paradis, Pointe-aux-Chenes, Venice.

A fourth of the state's wetlands are already gone, with heavy losses tallied from 2005 to 2008, when the coast was battered in succession by Hurricanes Katrina, Rita, Gustav and Ike. In 2011, the federal government retired 35 place names for islands and bays and passes and ponds that had simply ceased to exist.

State planners believe another 2,000 square miles, or even double that, could be overtaken in 50 years as the land sinks, canals widen and sea levels rise because of climate change. Recent studies show that glacial melting is accelerating in Antarctica and Greenland, driving sea level rise on the Gulf Coast.

Although the recession of Louisiana's coast has slowed somewhat this decade, a football field's worth of the state's wetlands still vanishes every 100 minutes, according to the United States Geological Survey. That is one of the highest rates on the planet, accounting for 90 percent of such losses in the contiguous United States.

The Gulf Restoration Network, a nonprofit conservation group, calculates that there are 358,000 people and 116,000 houses in Louisiana census tracts that would be swamped in the surge of a catastrophic hurricane by 2062. The Geological Survey predicts that in 200 years the state's wetlands could be gone altogether.

"It is the largest ecological catastrophe in North America since the Dust Bowl," declared Oliver Houck, a professor of environmental law at Tulane University who has written extensively about land loss in the state.

Oil industry infrastructure in wetlands south of Lafitte. (William Widmer, The New York Times)

In addition to the effects of climate change, human engineering has contributed broadly to the losses. Since the early 18th century, the construction of levees on the Mississippi and the closing of its distributaries have altered natural hydrology and stifled land-building silt deposits from spring floods. Property owners and government regulators have allowed the degradation of swamp and marshland, first for farming and cypress-logging and then, more insatiably, for oil and natural gas exploration.

Since prospectors first discovered oil in Louisiana 117 years ago, 57,465 wells have been drilled in 10 coastal parishes, according to the state's Department of Natural Resources. Thousands of miles of canals have been dredged through marshes for access. They broaden each year from erosion caused by boat traffic and storm currents, even as their spoil banks block natural water flow. A 50,000-mile thicket of pipelines connects rigs to refineries and tank farms across the state.

After years of laissez-faire regulation, some consequential finger-pointing has begun in the courts, where parish governments and private landowners are for the first time suing energy companies to rebuild their land. To date that burden has fallen mostly on taxpayers, even when the property being repaired is owned by oil and gas interests, an examination of state records shows.

The impact extends far beyond Louisiana's shoreline.

The slender coastal zone, stretching west from Breton Sound across the mouth of the Mississippi to Sabine Pass, contains 37 percent of the estuarine marsh and the largest commercial fishery in the contiguous 48 states. Its ports support 24 percent of the nation's waterborne commerce and a fifth of its oil supply. The coast provides winter habitat for five million migratory waterfowl. Along with man-made levees and floodwalls, it is the buffer that keeps the Gulf of Mexico from draining into New Orleans, much of which sits below sea level.